Significant quantities of water are produced in the extraction of hydrocarbon energy resources (currently estimated at approximately 14 billion barrels per year (bbl/yr) across the United States [1 bbl=42 gallons]). Produced water includes water that is brought to the surface during oil and gas exploration and production, often having been trapped in underground formations for centuries. Additionally, produced water can be generated from scrubbers in power plants, dewatering and extracting uranium resources, carbon sequestration, and development of unconventional energy sources. Produced water from any application often contains significant amounts of hydrocarbons such as crude oil that may prevent the produced water from being reused in other applications. Thus, there are ongoing needs for apparatus and methods to process large volumes of produced water, particularly to remove the contaminants such as hydrocarbons from the produced water.
Ceramic membranes have limited ability to process waters such as produced water, owing to the high likelihood that the membranes may be subject to total fouling or even mechanical failure when oil and other hydrocarbons, sand, salt and other chemicals are contacted with or passed through the ceramic membranes. Thus, there are ongoing needs for improved ceramic membranes that may be able to continually filter produced water without becoming irreversibly disabled by total fouling.
Fixed bed or fluidized bed filtration may also be used to adsorb organic contaminants from produced water. During such processes, contaminants in the produced water may be trapped in a layer of particles or adsorbed onto the particles. Eventually, the particles need to be cleaned or replaced. Cleaning or replacing the particles involves added costs. Thus, there are ongoing needs for filtration processes that enable particles to be cleaned or recycled in an efficient manner.
Regardless of the filtration process used to process produced water, hydrocarbons such as crude oil that are removed from the produced water typically are discarded as waste materials. These types of waste may have a detrimental environmental impact. Moreover, the hydrocarbons themselves may have true monetary value that is unrealized when the hydrocarbons are simply discarded. Thus, there are ongoing needs for systems that may be capable of minimizing hydrocarbon waste from produced water processing, as well as enabling value to be realized from the hydrocarbons recovered in process conditions compatible with hydrocarbons production and their downstream operations.